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| author | Daniel Kurtz <djkurtz@chromium.org> | 2012-07-24 14:13:57 +0200 |
|---|---|---|
| committer | Jean Delvare <khali@endymion.delvare> | 2012-07-24 14:13:57 +0200 |
| commit | efa3cb15ad8ba40bd08b05df87ef0ca6680ef762 (patch) | |
| tree | affbc114b7f751f8308a834b39b8d34972191ac1 /drivers/i2c/busses | |
| parent | fda2f4af37ccc80d655a5b4538288d461539b574 (diff) | |
| download | op-kernel-dev-efa3cb15ad8ba40bd08b05df87ef0ca6680ef762.zip op-kernel-dev-efa3cb15ad8ba40bd08b05df87ef0ca6680ef762.tar.gz | |
i2c-i801: Refactor use of LAST_BYTE in i801_block_transaction_byte_by_byte
As a slight optimization, pull some logic out of the polling loop during
byte-by-byte transactions by just setting the I801_LAST_BYTE bit, as
defined in the i801 (PCH) datasheet, when reading the last byte of a
byte-by-byte I2C_SMBUS_READ.
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'drivers/i2c/busses')
| -rw-r--r-- | drivers/i2c/busses/i2c-i801.c | 28 |
1 files changed, 14 insertions, 14 deletions
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index ae2945a5..51e11eb 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -117,8 +117,7 @@ #define I801_PROC_CALL 0x10 /* unimplemented */ #define I801_BLOCK_DATA 0x14 #define I801_I2C_BLOCK_DATA 0x18 /* ICH5 and later */ -#define I801_BLOCK_LAST 0x34 -#define I801_I2C_BLOCK_LAST 0x38 /* ICH5 and later */ +#define I801_LAST_BYTE 0x20 #define I801_START 0x40 #define I801_PEC_EN 0x80 /* ICH3 and later */ @@ -338,6 +337,11 @@ static int i801_block_transaction_by_block(struct i801_priv *priv, return 0; } +/* + * For "byte-by-byte" block transactions: + * I2C write uses cmd=I801_BLOCK_DATA, I2C_EN=1 + * I2C read uses cmd=I801_I2C_BLOCK_DATA + */ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, union i2c_smbus_data *data, char read_write, int command, @@ -360,19 +364,15 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, outb_p(data->block[1], SMBBLKDAT(priv)); } + if (command == I2C_SMBUS_I2C_BLOCK_DATA && + read_write == I2C_SMBUS_READ) + smbcmd = I801_I2C_BLOCK_DATA; + else + smbcmd = I801_BLOCK_DATA; + for (i = 1; i <= len; i++) { - if (i == len && read_write == I2C_SMBUS_READ) { - if (command == I2C_SMBUS_I2C_BLOCK_DATA) - smbcmd = I801_I2C_BLOCK_LAST; - else - smbcmd = I801_BLOCK_LAST; - } else { - if (command == I2C_SMBUS_I2C_BLOCK_DATA - && read_write == I2C_SMBUS_READ) - smbcmd = I801_I2C_BLOCK_DATA; - else - smbcmd = I801_BLOCK_DATA; - } + if (i == len && read_write == I2C_SMBUS_READ) + smbcmd |= I801_LAST_BYTE; outb_p(smbcmd | ENABLE_INT9, SMBHSTCNT(priv)); if (i == 1) |
